Generally, two semiconductor dies may be connected using through-silicon vias (TSVs), which generally require some type of removal of material from the backside of the wafers on which the semiconductor dies are formed. In one method of forming TSVs, a portion of the side of the wafer containing active devices is removed to form one or more holes at least part of the way through the silicon wafer. After the holes have been filled with a conductive material, the backside of the wafer is removed using a process such as mechanical grinding or etching in order to expose the conductive material and form a contact through the backside of the wafer to the front side of the wafer.
However, as materials such as low-k or extremely low-k dielectrics are beginning to become more widely used, these methods become a problem. These materials are very fragile and do not withstand the stresses from various process steps very well. This problem becomes magnified when the wafers are thinned by mechanical grinding or etching as the dielectrics may become unable to stand further handling and processing, which may result in damage and, eventually, device failure.
As such, what is needed is a new method of forming TSVs that reduce or prevent damage to a thinned wafer during subsequent handling and processing.